1. Field of the Invention
The present invention relates generally to the control of optical beam processing and, more specifically, the present invention relates to the control of systems that switch or route optical signals.
2. Background Information
The need for fast and efficient optical processing and switching is increasing as Internet data traffic growth rate is overtaking voice traffic pushing the need for optical communications. Two commonly found types of optical switches are mechanical switching devices and electro-optic switching devices.
Mechanical switching devices generally involve physical components that are placed in the optical paths between optical fibers. These components are moved to cause switching action. Micro-electronic mechanical systems (MEMS) have recently been used for miniature mechanical switches. MEMS are popular because they are silicon based and are processed using somewhat conventional silicon processing technologies. However, since MEMS technology generally rely upon the actual mechanical movement of physical parts or components, MEMS are generally limited to slower speed optical applications, such as for example applications having response times on the order of milliseconds.
In electro-optic switching devices, voltages are applied to selected parts of a device to create electric fields within the device. The electric fields change the optical properties of selected materials within the device and the electro-optic effect results in switching action. Electro-optic devices typically utilize electro-optical materials that combine optical transparency with voltage-variable optical behavior. One typical type of single crystal electro-optical material used in electro-optic switching devices is lithium niobate (LiNbO3).
All types of optical switching devices require accurate alignment of the optical beams exiting the component to the receiving optical fiber(s) or ports. The mechanisms controlling this alignment can drift and age with time and material fatigue and in response to variations in the drive circuitry, temperature, and other factors.